What Is VAT Polymerization in 3D Printing?


3D printing processes have evolved over the years. While some of them simply allow the deposited material to air-dry, others use faster and more advanced curing methods. VAT polymerization is one such 3D printing technology that uses an alternative curing method. Rather than air-drying, it uses ultraviolet (UV) light to cure the material. What is VAT polymerization exactly, and how does it stack up against other 3D printing processes?

Overview of VAT Polymerization

VAT polymerization is a group of 3D printing processes that’s characterized by its use of UV light for curing purposes. 3D printers generally don’t deposit solid material. Rather, the material is highly viscous when it’s deposited onto the 3D print bed. The material must then be cured to develop a hard texture and, therefore, form the desired object. VAT polymerization processes use UV light to cure material in a prefilled vat.

Some of the most common VAT polymerization processes include the following:

  • Stereolithography
  • Direct light processing
  • Masked stereolithography

VAT Polymerization vs FFF

VAT polymerization differs from fused filament fabrication (FFF) in several ways. One of the biggest differences between them is that the latter 3D printing method deposits material, whereas the former method does not. FFF 3D printers are designed to deposit material onto a print bed by extruding it out of a nozzle. The FFF 3D printer’s nozzle will move over the print bed while depositing material. In comparison, VAT polymerization 3D printers simply cure material that’s already filled within a container known as vat.

VAT polymerization and FFF 3D printers also use different materials. FFF 3D printers use thermoplastics as the raw material from which they build objects, whereas VAT polymerization 3D printers use a special type of UV-sensitive material known as photopolymer resin.

Of course, only VAT 3D printers use UV light to cure their material. After all, the use of UV light is what distinguishes them from all other 3D printers, including FFF 3D printers. VAT 3D printers work by selectively curing particles of photopolymer resin within a vat. The vat is filled with photopolymer resin, after which a UV light selectively cures the material to build the desired object.

There are other 3D printing methods besides VAT polymerization and FFF. Of all the methods available, though, VAT polymerization is the only one that uses UV light to cure material in a pre-filled vat. It selectively cures photopolymer resin in a vat to build objects.